Bailleul inspected the fossils from a collection at the Rocky Mountain Museum in Bozeman, Montana, to see how the dinosaurs’ skulls developed. But what caught her attention, the textbooks said, should not be there. Embedded in calcified cartilage at the back of the skull were what appeared to be fossilized cells. Some contained tiny nucleus-like structures. In one it was something like a cluster of chromosomes, the strands that carry an organism’s DNA. Bailleul showed the samples to Mary Schweitzer, a professor and molecular paleontologist at the University of North Carolina, who was visiting the museum. Schweitzer did her PhD in Montana under the supervision of Jack Horner, the resident fossil hunter who inspired Jurassic Park character Alan Grant. Schweitzer herself had become famous – and faced with waves of criticism – for claiming to have found soft tissue in dinosaur fossils, from blood vessels to protein fragments. Schweitzer sparked interest in Bailleul’s discovery, and the two joined forces to study the fossils further. In early 2020, as people faced the arrival of Covid, they published a bomb-document about their findings. Their report provided not only evidence of dinosaur cells and nuclei in the Chandrosaur fossils, but also results from chemical tests showing DNA, or something similar, wrapped inside. I do not think we should rule out taking dinosaur DNA from dinosaur fossils – but we would not if we did not continue to look at Mary Schweitzer The idea of recovering biological material from dinosaur fossils is controversial and profound. Schweitzer does not claim to have found dinosaur DNA – evidence is too weak to be sure – but says scientists should not rule out the possibility of it remaining in prehistoric remains. “I do not think we should ever rule out getting dinosaur DNA from dinosaur fossils,” he says. “We are not there yet, and we may not find it, but I guarantee we will not find it if we do not continue to search.” Remains of prehistoric tissue, proteins or DNA could transform the field of molecular paleontology and unlock many of the mysteries of dinosaur life. But the prospect of having the intact genetic code from a tyrannosaurus or a cyclist raises questions that scientists are accustomed to looking at from the original Jurassic Park movie in 1993. Armed with adequate DNA DNA, could we bring back the beasts that were beaten? An artist’s impression of the woolen mammoth. Photo: David Fleetham / Alamy Rapid advances in biotechnology have paved the way for sophisticated approaches to extinction, where a species once considered extinct is receiving a second shot at life on Earth. At the moment, the focus is on the creatures with which humans once shared the planet – and which we have helped drive out of existence. Undoubtedly the most high-profile liberation program aims to recreate, in a way, the woolly mammoth and return herds of beasts to the Siberian tundra thousands of years after their extinction. The company behind the project, Colossal, was founded by Harvard geneticist George Church and Ben Lam, a technology businessman, who claim that thousands of mammoths could help restore the degraded habitat: for example, by cutting down trees, fertilizing soil with their manure and encourage the meadows to sprout again. If all goes according to plan – and maybe not – the first calves could be born in six years. What lies ahead is a formidable challenge. Despite the well-preserved mammoths excavated from the tundra, no living cells were found to clone them using the approach produced by Dolly the sheep, the first cloned mammal. So Colossal came up with a solution. The team initially compared the genes of a woolly mammoth and a close relative who lived, the Asian elephant. This revealed genetic variants that equipped the woolly mammoth for the cold: thick hair, shorter ears, thick layers of fat for insulation, and so on. The next step is to use gene processing tools to rewrite the genome of an Asian elephant cell. If the approximately 50 expected modifications have the desired effect, the team will introduce one of the “mammoth” elephant cells into an Asian elephant that has removed the nucleus. An electric current will be applied to the spark fertilization and the egg will begin to divide and grow into an embryo. Finally, the embryo will be transferred to a surrogate mother or, given the goal of producing thousands of creatures, into an artificial uterus that can carry the fetus to maturity. Colossal’s work highlights one of the biggest misconceptions about liberation programs. Despite the talk of restoring the species, these will not be replicas of extinct animals. Colossal mammoth wool, as the Church easily admits, will be an elephant that will be modified to survive the cold. Whether this matters depends on the motivation. If the goal is to restore the health of an ecosystem, then the animal’s behavior outweighs its identity. But if the driver is nostalgia, or an attempt to appease human guilt for the destruction of a species, removal may be more than a scientific strategy to fool ourselves. Elizabeth Ann, the first cloned black-footed ferret, is about seven weeks old. Photo: US Fish & Wildlife Service / AP The California-based nonprofit Revive and Restore is working on projects to help revive more than 40 species through the perceptive application of biotechnology. The body has cloned a black-legged ferret named Elizabeth Ann, which will become the first cloned mammal to help rescue an endangered species. The hope is that Elizabeth Ann, created from frozen cells in the 1980s, will bring much-needed genetic diversity to wild breeds of incest-threatened ferrets. Revive and Restore plans to bring back two extinct bird species, the heather and the passenger pigeon, by the 2030s. As part of the release plan, the scientists will create a replacement bird by processing the DNA of the closely related chicken meadow carrying chicken genes. The passenger pigeon project follows a similar approach, using the tail pigeon as a genetic model. Ben Novak, chief scientist at Revive and Restore, likens extinction to restoration efforts to reintroduce lost species to improve local habitats. “The introduction of biotechnology is just extending this existing practice so that we can look at species that were off the table before,” he says. To worry that animals created through release programs are not exact replicas of lost species makes sense, he adds. “We do not recreate these species to satisfy human philosophy – we do so for conservation reasons. “For conservation, what matters is an ecosystem, and ecosystems are not based on classification systems.” Should people try to prevent all future disappearances? Every species dies at some point. But while extinction is normal in ecosystem evolution, human activity is driving species to the brink faster than most species can adapt. Novak says preventing all extinctions is a “good goal”, but the reality, he adds, is that the world’s governments have not given priority to conservation over exploitation. “No matter how many people work really hard, we have the majority of humanity still working against this goal,” he says. “What we can do is prevent as many as possible right now and re-diversify the world in a way that gives us ecological stability to prevent further extinctions.” The dodo: without a habitat to thrive, it makes no sense to resurrect it. Photo: Leemag / Corbis / Getty Images Dodo is the main candidate for release. Once native to Mauritius (and only in Mauritius), the great bird that did not fly died in the 17th century after humans settled on the island. In addition to the extensive destruction of its habitat, the dodo was further threatened by pigs, cats and monkeys brought with it by sailors. A team led by Beth Shapiro, a professor of ecology and evolutionary biology at the University of California, Santa Cruz, analyzed the dodo genome sequence from a sample museum in Copenhagen. Theoretically, a dodo-like bird could be created by processing the Nicobar pigeon genome to contain dodo DNA, but, as with all extinction projects, creating an animal is not enough: there must be a habitat for it to thrive. . , or the exercise becomes pointless. “I think it’s important, as we prioritize species and ecosystems for protection, to do so given what our planet will be like 50 or 100 years from now, instead of imagining that we can somehow turn the clock back and “to restore the ecosystems of the past,” says Shapiro. “The biggest problem facing many species today is that the rate of change of their habitats is too fast for evolution to keep pace. Here our new technologies can be useful. We can sequence genomes and make more informed reproduction decisions. We can resurrect lost diversity by cloning – like Elizabeth Ann, the black-legged ferret – and perhaps even be able to move adaptive traits between populations and species. “Our new technologies can allow us to increase the rate at which species can adapt, perhaps saving some of the same fate as dodo and mammoth.” The preserved and stuffed trunk of a young woolly mammoth, found frozen in Siberia. Photo: VPC Travel Photo / Alamy Most release projects are viable because researchers have either living cells or …
